Characterization of Adult Patients With SMA Treated in US Hospital Settings: A Natural History Study in the Premier...

Spinal muscular atrophy (SMA) is a rare genetic disease characterized by progressive muscular weakness and atrophy resulting from motor neuron degeneration. Limited information is available on disease progression among older SMA patients, particularly adults.

This study sought to characterize the natural history of SMA among adult patients in US hospital settings through the assessment of symptoms, complications, costs, and healthcare resource utilization (HRU) over 3 years before the availability of disease-modifying therapies.

The study population included adult (≥18 years) patients with inpatient and/or hospital-based outpatient discharge records and ≥2 primary or secondary SMA ICD-9 codes ≥30 days apart in the Premier Healthcare Database during the main study period (2007-2014). Index date was the date of the first SMA ICD-9 code. The frequency of SMA-related symptoms and complications was assessed 1 year preindex through 2 years postindex to characterize disease progression. Costs and HRU were also assessed across the study period.

A total of 446 adult patients from 337 US hospitals met inclusion criteria for these analyses. All evaluated SMA-related symptoms and complications increased steadily over time, from 1 year preindex to 2 years postindex both overall and in each age group. Adult patients with SMA had increasing total costs and HRU over the 3-year study period: total costs were $1,759 preindex and $12,308 by 2 years postindex.

Findings are consistent with increasing disease burden over time and support the progressive nature of SMA for adult patients with hospital interactions.